The present disclosure relates to magnetic devices such as a magnetic memory device or a spin logic device. More particularly, the principles of the present disclosure relate primarily to a contact structure that is coupled to a magnetic element such as a magnetic tunneling junction (MTJ) structure and is capable of compensating for an offset field, and to a method of manufacturing the same.
Successful application of spin-transfer torque in magnetic devices, including spin transfer torque random access memory (STT-RAM) devices, requires overcoming a number of challenges. For example, an undesirable offset field on a free layer in a MTJ structure may need to be minimized for more stable operation of magnetic devices.
In particular, in a magnetic device, dipolar coupling or dipolar interaction can occur between a reference layer and the free layer due to the dipolar or stray fields exerted therefrom. If such dipolar interaction is significant, an undesirable offset field can be felt at the free layer. In that case, a hysteresis loop of the free layer becomes offset from a zero magnetic field, making operation of the magnetic device more difficult and significantly increasing power consumption. Furthermore, these dipolar or stray fields from the reference layer(s) can interact with adjacent free layers of adjacent magnetic elements or magnetic memory cells, which may further disrupt the operation of the magnetic device. Reducing the offset field can be an issue for any magnetic device. However, the problem of minimizing the offset field becomes increasingly difficult with the scaling down of the magnetic devices.
For these reasons, without reducing the offset field to an acceptable level, the magnetic devices may not provide a viable option for the electronic industry, and may not provide a suitable replacement for conventional semiconductor devices such as dynamic random access memory (DRAM), flash memories, and static random access memories (SRAMs) as hoped.